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Subject: Re: [PATCH for v5.9] mm/page_alloc: handle a missing case for
 memalloc_nocma_{save/restore} APIs
To:     Joonsoo Kim <js1304@gmail.com>,
        Mel Gorman <mgorman@techsingularity.net>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Linux Memory Management List <linux-mm@kvack.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Michal Hocko <mhocko@kernel.org>,
        "Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>,
        kernel-team@lge.com, Joonsoo Kim <iamjoonsoo.kim@lge.com>
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From:   Vlastimil Babka <vbabka@suse.cz>
Message-ID: <d587d057-75f1-288e-49d2-0c6ea387d414@suse.cz>
Date:   Fri, 25 Sep 2020 10:55:36 +0200
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On 9/25/20 6:59 AM, Joonsoo Kim wrote:
> 2020년 8월 28일 (금) 오전 8:54, Joonsoo Kim <js1304@gmail.com>님이 작성:
> 
> Hello, Andrew and Vlastimil.
> 
> It's better to fix this possible bug introduced in v5.9-rc1 before
> v5.9 is released.
> Which approach do you prefer?
> If it is determined, I will immediately send a patch as you suggested.

Hmm both Mel and I preferred the bypass approach and nobody else weighted in, so
if you don't mind, you can use my suggestion. Hmm maybe alloc_flags & ALLOC_CMA
check should precede migratetype check in the if () to optimize for userspace
allocations?

Thanks,
Vlastimil

> Thanks.
>